A wire harness is an electric wiring system comprising a large number of electric wires, terminals, connectors and the like to be incorporated in a motor vehicle, a copying apparatus or the like.
Since it is difficult to specify the form, such a wire harness is generally laid out on a working table called a drawing plate to shape the final form thereof, and then connected, on the drawing plate, to externally mounted parts such as protectors, grommets and the like (See, for example, Japanese Utility Model Laid-Open Publication No. 4-99313).
To hold the wire harness on the drawing plate, a large number of jigs are fixed on the drawing plate. Each of these jigs is usually made of a metallic member having a substantially U-shape section of which the top is opened.
Also disposed on the drawing plate are jigs incorporating detecting switches for detecting externally mounted parts. The detecting switches are electrically connected to a controller. Each detecting switch is adapted to transmit a detection signal to the controller when the detecting switch detects an externally mounted part to be assembled in the production process. When all the detecting switches have transmitted the detection signals to the controller, the controller not only actuates an informing mechanism such as an acceptance buzzer, a pilot lamp or the like, but also actuates an acceptance stamp sealing machine. The acceptance stamp sealing machine is adapted to seal an acceptance stamp on a product number label. The operator can be aware of the fact that the process has been finished upon actuation of the informing mechanism. Further, the operator can visually make sure that the assembly acceptance stamp has securely been sealed.
The completed wire is then subjected to an inspection process including an electrical conduction inspection, an appearance inspection and the like. Conventionally, once a wire harness was removed from the drawing plate for production and then placed on another drawing plate for inspection in order to carry out above mentioned inspection process. However, such an inspection process may recently be carried out upon while the wire harness is on the same drawing plate as that used in the production process.
To conduct an electrical conduction inspection in the inspection process, an electrical conduction testing device is placed on the drawing plate. The conduction testing device is electrically connected to conduction inspecting jigs for judging whether or not the electrical conduction of connector housings, terminals and the like of a wire harness is good.
When inspection signals are transmitted from all the conduction inspecting jigs to the conduction testing device, the conduction testing device judges that the conduction of the wire harness is good. Then, the conduction testing device actuates the informing mechanism incorporated therein to inform the operator of the judging result, and also actuates the acceptance stamp sealing machine such that an inspection acceptance stamp is sealed. Thus, the operator can be aware of the fact that the process has been finished upon actuation of the informing mechanism, and then visually makes sure that the inspection acceptance stamp has securely been sealed.
Such processes of producing and inspecting a wire harness on a drawing plate present the following problems.
First, the following problems are encountered in the production process.
The wire harness is merely carried by the substantially U-shape metallic jigs. Accordingly, the wire harness is liable to come off from the jigs during the production process, thus lowering the working efficiency. That is, when attaching parts to the wire harness, it is required to attach such parts while force is applied to the wire harness or while a portion of the wire harness is carried under an arm of the operator.
Often, the informing mechanism for informing the completion of the production process, is the same as that used in the other production line. Accordingly, there have been instances where an unfinished wire harness has erroneously been removed from the drawing plate due to a mistake of the operator or when the operators are changed in the middle course of the work.
In view of the foregoing, the present invention is proposed with the object of providing a wire harness holding device and wire harness holding mechanism and method using this wire harness holding device capable of not only preventing a wire harness from unduly coming off from jigs, but also preventing defective products from being sent to subsequent steps.
In the inspection process, visual examination is exclusively carried out in order to judge whether or not the inspection acceptance stamp has securely been sealed, or whether or not the electrical conduction test has successfully been finished. This involves the likelihood, as a consequence of human factors, that there remain some parts not inspected yet or a wire harness presenting a defective sealing is removed from the drawing plate.
For the foregoing reasons, there is a need for a wire harness holding device and wire harness holding mechanism and method using the wire harness holding device above-mentioned capable of securely preventing an unfinished product from being removed as a consequence of human factors.